Software signature discovery

ABSTRACT

In a method for determining and scoring signatures for a software package, a processor compares files on a clean computer system after installation of a software package to files on the clean computer system before the installation. The processor determines a signature of the software package. The signature includes files on the clean computer system after installation of the software package that were not present on the clean computer system before the installation.

FIELD OF THE INVENTION

The present invention relates generally to the field of computersoftware and more particularly to a method for generating and scoring asignature for a software package.

BACKGROUND OF THE INVENTION

Computer software is fundamentally a set of instructions written tocarry out a desired task. Computer software can be stored anddistributed in many forms, including but not limited to local storagesuch as hard disk drives and optical media (e.g. compact discs),networked storage devices, and even non-digital media (e.g. punchcards). The highly portable nature of computer software, and otherdigital content, facilitates duplication and distribution. Computersoftware can be made up of many individual software components, such asfiles or executable programs, which are typically encapsulated in anexecutable installation package for ease of distribution. Theinstallation package will typically include an executable program toremove, or uninstall, the computer software. Computer software is alsofrequently modified and updated.

Software deployment is the process of making computer software availablefor use on a computer system. Conventional software deployment involvescopying an installation package to the local storage of a computersystem and executing the installation package to place the individualsoftware components on the system. In a network environment, wherecomputer software must be deployed to multiple computer systems, thisprocess is typically automated. Furthermore, in network environments,the installation package is typically executed remotely on a networkedstorage device and only the individual software components from withinthe installation package are copied to the multiple computer systems.

The use and distribution of commercially available computer software istypically controlled by software licenses. Depending on the level ofsoftware license purchased, the computer software may be fully activatedor some features may be limited. Different software license options aretypically available for the level of features desired and the number ofcomputer systems that may use the software package under a singlesoftware license.

Software asset management typically refers to the tracking andmanagement of computer software installed on a computer system for thepurposes of keeping the computer software up to date, identifyingconflicts, managing software licenses, and tracking software usage.Software asset management solutions are typically employed in largeorganizations where numerous packages of computer software are deployedto a multitude of computer systems in a networked environment.

SUMMARY

Aspects of the present invention disclose a method, system, and computerprogram product for determining and scoring a signature for a softwarepackage. At least one processor compares files on a clean computersystem after installation of a first software package to files on theclean computer system before installation. The at least one processordetermines a first signature of the first software package, wherein thefirst signature comprises files on the clean computer system afterinstallation of the first software package that were not present on theclean computer system before installation.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a functional block diagram illustrating a computer system, inaccordance with an embodiment of the present invention.

FIG. 2 depicts a flowchart of a software signature capturing program fordetermining and scoring a software signature for a software package, inaccordance with one embodiment of the present invention.

FIG. 3A depicts a use-case scenario of capturing system snapshots anddetermining and scoring a software signature for a software package, inaccordance with one embodiment of the present invention.

FIG. 3B depicts a use-case scenario of assigning scores to softwaresignatures in accordance with one embodiment of the present invention.

FIG. 4 depicts a block diagram of components of the computer system ofFIG. 1, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer-readablemedium(s) having computer-readable program code/instructions embodiedthereon.

Any combination of computer-readable media may be utilized.Computer-readable media may be a computer-readable signal medium or acomputer-readable storage medium. A computer-readable storage medium maybe, for example, but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, ordevice, or any suitable combination of the foregoing. More specificexamples (a non-exhaustive list) of a computer-readable storage mediumwould include the following: an electrical connection having one or morewires, a portable computer diskette, a hard disk, a random access memory(RAM), a read-only memory (ROM), an erasable programmable read-onlymemory (EPROM or Flash memory), an optical fiber, a portable compactdisc read-only memory (CD-ROM), an optical storage device, a magneticstorage device, or any suitable combination of the foregoing. In thecontext of this document, a computer-readable storage medium may be anytangible medium that can contain, or store a program for use by or inconnection with an instruction execution system, apparatus, or device.

A computer-readable signal medium may include a propagated data signalwith computer-readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer-readable signal medium may be any computer-readable medium thatis not a computer-readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer-readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on a user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in acomputer-readable medium that can direct a computer, other programmabledata processing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer-readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce acomputer-implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The present invention will now be described in detail with reference tothe Figures. FIG. 1 is a functional block diagram illustrating acomputer system, in accordance with an embodiment of the presentinvention. FIG. 1 provides only an illustration of one embodiment anddoes not imply any limitations with regard to the environments in whichdifferent embodiments may be implemented.

In the depicted embodiment, computer system 10 may be a desktopcomputer, laptop computer, tablet computer, personal digital assistant(PDA), or smart phone. In other embodiments, computer system 10 mayrepresent any electronic device or computer system capable of sendingand receiving data and executing program instructions. Computer system10 includes a software installer program 20, software installation files30, software signatures 40, and software signature capturing program 50.

Software installer program 20 operates to install, uninstall, and managesoftware on computer system 10. In one embodiment, software installerprogram 20 resides on computer system 10. In other embodiments, softwareinstaller program 20 may reside on another computer system or computingdevice, provided that software installer program 20 has access tosoftware installation files 30 and that software installer program 20can communicate with computer system 10. For example, software installerprogram 20 may reside on a computing device connected to computer system10 over a network (such as a local area network, wide area network, theInternet, or any combination thereof).

Software installation files 30 are files that may be read by softwareinstaller program 20. In one embodiment, software installation files 30may be in the form of standalone files, an archive of files, anexecutable file, or any combination thereof. In one embodiment, softwareinstallation files 30 resides on computer system 10. In otherembodiments, software installation files 30 may reside on anothercomputer system or computing device, provided that software installationfiles 30 is accessible to software installer program 20. For example,software installation files 30 may reside on a computing deviceconnected to computer system 10 over a network (such as a local areanetwork, wide area network, the Internet, or any combination thereof).

Software signatures 40 may be a file written to and read by softwaresignature capturing program 50. In another embodiment, softwaresignatures 40 may be a database such as Oracle® or an IBM® BD2®database. In one embodiment, software signatures 40 resides on computersystem 10. In other embodiments, software signatures 40 may reside onanother computer system or computing device, provided that softwaresignatures 40 is accessible to software signature capturing program 50.For example, software signatures 40 may reside on a computing deviceconnected to computer system 10 over a network (such as a local areanetwork, wide area network, the Internet, the public switched telephonenetwork, or any combination thereof).

In one embodiment, software signatures 40 includes one or more softwaresignatures determined by software signature capturing program 50. Asoftware signature is associated with a software package installed oncomputer system 10. A software signature may be a listing of any fileadded to or modified on computer system 10 after a software package isinstalled to the clean system (i.e. computer system 10 includes onlysoftware signature capturing program 50, apart from the softwarerequired to run the system, such as an operating system).

Software signatures 40 may also include snapshots of computer system 10.The snapshot of a computer system may include the names and locations ofall files residing on that computer system at the time of the snapshot.The snapshot may store additional information associated with each filein the snapshot including, but not limited to, file size, creation date,and date last modified. Software signatures 40 may include multiplesnapshots per computer system, each snapshot corresponding with adifferent state (i.e. amount of software installed on the computersystem at any given time) of the computer system. Software signatures 40may also include a score associated with each software signature storedby software signature capturing program 50.

Software signature capturing program 50 operates to determine and scorea software signature for a software package installed on computer system10. Software signature capturing program 50 also operates to storesnapshots of computer system 10. The snapshot of a computer system mayinclude the names and locations of all files residing on that computersystem at the time of the snapshot.

In one embodiment, software signature capturing program 50 resides oncomputer system 10. In another embodiment, software signature capturingprogram 50 may be a function of software installer program 20. In otherembodiments, software signature capturing program 50 may reside onanother computer system or computing device, provided that softwaresignature capturing program 50 has access to computer system 10 andsoftware signatures 40, and provided that software signature capturingprogram 50 can communicate with software installer program 20. Forexample, software signature capturing program 50 may reside on acomputing device connected to computer system 10 over a network (such asa local area network, wide area network, the Internet, or anycombination thereof).

FIG. 2 depicts a flowchart of software signature capturing program 50for determining and scoring a software signature for a software packagein accordance with one embodiment of the present invention. Initially,multiple software packages (i.e. multiple programs to be installed) areselected for which software signatures and corresponding scores are tobe generated. The installation files for these software packages are insoftware installation files 30. In one embodiment, software signaturecapturing program 50 is started by the user.

In step 200, software signature capturing program 50 captures a snapshotof computer system 10. Computer system 10 initially includes onlysoftware signature capturing program 50 apart from software required torun the system, such as an operating system (i.e. computer system 10 isa ‘clean’ system). To create snapshots, software signature capturingprogram 50 traverses the entire local storage of computer system 10 andcreates a listing of the names and locations of all files residingcomputer system 10 at the time of the snapshot. The snapshot may storeadditional information associated with each file in the snapshotincluding, but not limited to, file size, creation date, and date lastmodified. Software signature capturing program 50 stores this snapshotin software signatures 40 as the pre-install system snapshot (i.e. theclean system snapshot).

Software installer program 20 is executed to install a software packagefrom software installation files 30 to computer system 10. In oneembodiment, the execution of software installer program 20 may beinitiated by another program. For example, a program running on acomputing device connected to computer system 10 over a network may sendan indication to software installer program 20, residing on computersystem 10, to begin installing the software package. In anotherembodiment, execution of software installer program 20 may be initiatedby a user. For example, a user may initiate software installer program20 to install the software package on computer system 10. Softwareinstaller program 20 copies the files pertaining to the software packagebeing installed (i.e. the ‘current software package’) from softwareinstallation files 30 to the local storage of computer system 10. Thelocations to which the files are copied may be user-defined orprescribed by a configuration file included in the installation files ofthe current software package.

In one embodiment, software installer program 20 sends an indication tosoftware signature capturing program 50 in response to a completedsoftware package installation. In another embodiment, software signaturecapturing program 50 may monitor the progress of software installerprogram 20 during the installation of the software package. In anotherembodiment, software signature capturing program 50 may be a function ofsoftware installer program 20. In another embodiment, software signaturecapturing program 50 may be started by a user in response to thesoftware package being installed on computer system 10.

In step 210, in response to the completed installation of the currentsoftware package, software signature capturing program 50 captures asnapshot of computer system 10, which includes the files from the cleansystem snapshot in addition to the files from the current softwarepackage. Software signature capturing program 50 stores this snapshot insoftware signatures 40 as the post-install system snapshot associatedwith the current software package.

Software installer program 20 is executed to uninstall (i.e. remove) thecurrent software package from computer system 10. In one embodiment, theexecution of software installer program 20 may be initiated by anotherprogram. For example, a program running on a computing device connectedto computer system 10 over a network may send an indication to softwareinstaller program 20, residing on computer system 10, to beginuninstalling the software package. In another embodiment, the executionof software installer program 20 may be initiated by a user. Forexample, a user may initiate software installer program 20 to uninstallthe software package from computer system 10. Software installer program20 removes the files pertaining to the software package from computersystem 10. The locations from which the files are removed may beuser-defined or prescribed by a configuration file included in theinstallation files of the current software package.

In one embodiment, software installer program 20 sends an indication tosoftware signature capturing program 50 in response to the completion ofthe software package removal. In another embodiment, software signaturecapturing program 50 may monitor the progress of software installerprogram 20 during the removal of the current software package. Inanother embodiment, software signature capturing program 50 may be afunction of software installer program 20. In another embodiment,software signature capturing program 50 may be started by a user inresponse to the current software package being uninstalled from computersystem 10.

In step 220, in response to the removal of the current software package,software signature capturing program 50 captures a snapshot of computersystem 10, which includes the files from the clean system snapshot inaddition to the files left over from the removal of the current softwarepackage. Software signature capturing program 50 stores this snapshot insoftware signatures 40 as the post-uninstall system snapshot associatedwith the current software package.

In step 230, software signature capturing program 50 determines thesoftware signature for current software package. In one embodiment, thesoftware signatures for the current software package are obtained bycomparing the pre-install system snapshot (i.e. clean system snapshot)with the post-install system snapshot associated with the currentsoftware package. In one embodiment, any file found in the post-installsystem snapshot that is not also found in the pre-install systemsnapshot may be marked as part of the software signature associated withthe current software package. In one embodiment, the comparison ofsystem snapshots may occur based only on the filenames in each snapshot.In another embodiment, the comparison may take into account changes inother information associated with each file in the snapshot including,but not limited to, file size, creation date, and date last modified.

In step 230, software signature capturing program 50 further determineswhether or not a file found in the post-install system snapshot that isnot also found in the pre-install system snapshot is a critical artifactof the software package. A critical artifact is a file that was removedwhen the software package was uninstalled (i.e. a critical artifact is afile that is not left behind after the software is uninstalled). In oneembodiment, the critical artifacts for the current software package thatwas uninstalled are obtained by comparing the post-install systemsnapshot with the post-uninstall system snapshot associated with thecurrent software package. In one embodiment, any file found in thepost-install system snapshot that is not also found in thepost-uninstall system snapshot may be marked as a critical artifact ofthe current software package. In one embodiment, the comparison ofsystem snapshots may occur based only on the filenames in each snapshot.In another embodiment, the comparison may take into account changes inother information associated with each file in the snapshot including,but not limited to, file size, creation date, and date last modified.

Any files discovered in step 230 that are not also critical artifacts ofthe uninstalled program are marked as non-critical artifacts (i.e. filesthat are left behind after the software has been uninstalled) of thecurrent software package.

In decision 240, software signature capturing program 50 determines ifthere is another software package for which a signature and score mustbe generated. In one embodiment, the installation of software packageson computer system 10 is automatically controlled by another programwhich sends an indication to software signature capturing program 50 toeither wait for another software package to be installed, or to continuerunning. In another embodiment, a user will indicate whether anothersoftware package is to be installed.

If software signature capturing program 50 determines that there isanother software package to be installed on computer system 10 (decision240, Yes branch), software capturing program 60 returns to step 210 tocapture the post-install system snapshot associated with the nextsoftware package being installed.

If software signature capturing program 50 determines that there isanother software package to be installed on computer system 10 (decision240, No branch), software capturing program 60 continues to step 250.

In step 250, software signature capturing program 50 determines a scorefor each software signature determined. The score assigned to eachsoftware signature is a measure of how accurately the presence of thatsoftware signature can point to the presence of the software package itcame from.

In one embodiment, the score assigned to each software signature dependson how many times the same file appears in software signatures 40(across multiple software packages) as well as in how many of thoseappearances is the file a critical artifact. For example, a single filemay be a critical artifact for two separate software packages, and alsobe a non-critical artifact for a third software package. The score forevery file begins at unity. For every duplicate appearance of a file insoftware signatures 40, the score for that file would be multiplied by aless-than-unity weight (e.g. 0.7), and if that appearance is also as anon-critical artifact, the score would be further multiplied by aless-than-unity weight (e.g. 0.5). In other embodiments, the scoring andweighting system may differ.

Software signature capturing program 60 stores the computed softwaresignatures and their respective scores in software signatures 40.

The following descriptions of FIG. 3A and FIG. 3B illustrate thedetermination of a software signature from system snapshots, as well asassigning scores to software signature.

FIG. 3 a depicts a use-case scenario of capturing system snapshots anddetermining and scoring a software signature in accordance with oneembodiment of the present invention. Table 300 shows the differentstages of system snapshots before and after installing ‘Program Alpha’on a clean system and the subsequent software signature obtained fromthe system snapshots. In one embodiment, the contents of table 300 wouldbe stored in software signatures 40. Before Program Alpha was installed,software signature capturing program 50 obtained the system snapshot forthe clean system (‘Clean System Files’ column in table 300), and filesA, B, and C make up the clean system snapshot. After installing ProgramAlpha, the post-install system snapshot (‘Post-Install Files’ column intable 300) shows files A, B, C, D, E, F, and G. From these two snapshotsit is possible to obtain the software signature for Program Alpha(‘Signature’ column in table 300) by selecting all of the files that arein the ‘Post-Install Files’ but are not in ‘Clean System Files’ (i.e.the relative complement of ‘Clean System Files’ with respect to ‘PostInstall Files’). This gives files D, E, F, and G as a software signaturefor Program Alpha.

Similarly, it is possible to identify the critical artifacts (‘CriticalArtifacts’ column in table 300) by selecting all of the files that arein the ‘Signature’ column but are not in ‘Post-Uninstall Files’ column(i.e. the relative complement of ‘Post-Uninstall Files’ with respect to‘Signatures’). This gives files F and G as critical artifacts, and allfiles for Program Alpha (D and E) are defined to be non-criticalartifacts.

FIG. 3 b depicts a use-case scenario of assigning scores to softwaresignatures in accordance with one embodiment of the present invention.Table 350 depicts the signatures for three installed software packages:Program Alpha, Program Gamma, and Program Zeta. The process foridentification of the software signature and critical artifacts ofProgram Alpha is explained in FIG. 3 a, and similar methods are used toobtain signatures for exemplary Programs Gamma and Zeta. Once thesoftware signatures for each software package have been identified, thesoftware signatures are assigned a score.

In one embodiment, scores start at unity, with files multiplied by aweight of 0.7 for each duplicate appearance, and also multiplied by 0.5for each occurrence that is a non-critical artifact. For example, file Dappears as a non-critical artifact in Program Alpha (multiply by 0.5 fornon-critical artifact), again as a critical artifact in Program Gamma(multiply by 0.7 for a repeated file), and again as a non-criticalartifact in Program Zeta (multiply by 0.5 for non-critical artifact,multiply by 0.7 for a repeated file). The total score for file D is1*0.5*0.7*0.5*0.7=0.123. Scores for software signatures E through G aresimilarly computed. The highest score is unity, and is only achievedwhen the file is a critical artifact and is not repeated in thesignature of other software packages.

FIG. 4 depicts a block diagram of components of computer system 10 inaccordance with an illustrative embodiment of the present invention. Itshould be appreciated that FIG. 4 provides only an illustration of oneimplementation and does not imply any limitations with regard to theenvironments in which different embodiments may be implemented. Manymodifications to the depicted environment may be made.

Computer system 10 includes communications fabric 402, which providescommunications between computer processor(s) 404, memory 406, persistentstorage 408, communications unit 410, and input/output (I/O)interface(s) 412. Communications fabric 402 can be implemented with anyarchitecture designed for passing data and/or control informationbetween processors (such as microprocessors, communications and networkprocessors, etc.), system memory, peripheral devices, and any otherhardware components within a system. For example, communications fabric402 can be implemented with one or more buses.

Memory 406 and persistent storage 408 are computer-readable storagemedia. In this embodiment, memory 406 includes random access memory(RAM) 414 and cache memory 416. In general, memory 406 can include anysuitable volatile or non-volatile computer-readable storage media.

Software installer program 20, software installation files 30, softwaresignatures 40, and software signature capturing program 50 are stored inpersistent storage 408 for execution by one or more of the respectivecomputer processors 404 via one or more memories of memory 406. In thisembodiment, persistent storage 408 includes a magnetic hard disk drive.Alternatively, or in addition to a magnetic hard disk drive, persistentstorage 408 can include a solid state hard drive, a semiconductorstorage device, read-only memory (ROM), erasable programmable read-onlymemory (EPROM), flash memory, or any other computer-readable storagemedia that is capable of storing program instructions or digitalinformation.

The media used by persistent storage 408 may also be removable. Forexample, a removable hard drive may be used for persistent storage 408.Other examples include optical and magnetic disks, thumb drives, andsmart cards that are inserted into a drive for transfer onto anothercomputer-readable storage medium that is also part of persistent storage408.

Communications unit 410, in these examples, provides for communicationswith other data processing systems or devices, including resources ofenterprise grid 112 and client devices 104, 106, and 108. In theseexamples, communications unit 410 includes one or more network interfacecards. Communications unit 410 may provide communications through theuse of either or both physical and wireless communications links.Software installer program 20, software installation files 30, softwaresignatures 40, and software signature capturing program 50 may bedownloaded to persistent storage 408 through communications unit 410.

I/O interface(s) 412 allows for input and output of data with otherdevices that may be connected to server computer 102. For example, I/Ointerface 412 may provide a connection to external devices 418 such as akeyboard, keypad, a touch screen, and/or some other suitable inputdevice. External devices 418 can also include portable computer-readablestorage media such as, for example, thumb drives, portable optical ormagnetic disks, and memory cards. Software and data used to practiceembodiments of the present invention, e.g., software installer program20, software installation files 30, software signatures 40, and softwaresignature capturing program 50, can be stored on such portablecomputer-readable storage media and can be loaded onto persistentstorage 408 via I/O interface(s) 412. I/O interface(s) 412 also connectto a display 420.

Display 420 provides a mechanism to display data to a user and may be,for example, a computer monitor.

The programs described herein are identified based upon the applicationfor which they are implemented in a specific embodiment of theinvention. However, it should be appreciated that any particular programnomenclature herein is used merely for convenience, and thus theinvention should not be limited to use solely in any specificapplication identified and/or implied by such nomenclature.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the Figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

What is claimed is:
 1. A method for determining and scoring a signaturefor a software package, the method comprising the steps of: at least oneprocessor comparing files on a clean computer system after installationof a first software package to files on the clean computer system beforeinstallation; the at least one processor determining a first signatureof the first software package, wherein the first signature comprisesfiles on the clean computer system after installation of the firstsoftware package that were not present on the clean computer systembefore installation; the at least one processor comparing filesremaining on the clean computer system after an uninstall of the firstsoftware package to the files on the clean computer system afterinstallation of the first software package; and the at least oneprocessor determining one or more critical artifacts of the firstsignature, wherein the one or more critical artifacts comprise files ofthe first signature not remaining on the clean computer system after theuninstall of the first software package.
 2. The method of claim 1,further comprising the steps of: the at least one processor comparingfiles on the clean computer system after installation of a secondsoftware package to files on the clean computer system beforeinstallation; and the at least one processor determining a secondsignature of the second software package, wherein the second signaturecomprises files on the clean computer system after installation of thesecond software package that were not present on the clean computersystem before installation.
 3. The method of claim 2, further comprisingthe steps of: the at least one processor comparing files remaining onthe clean computer system after an uninstall of the second softwarepackage to the files on the clean computer system after installation ofthe second software package; and the at least one processor determiningone or more critical artifacts of the second signature, wherein the oneor more critical artifacts comprise files of the second signature notremaining on the clean computer system after the uninstall of the secondsoftware package.
 4. The method of claim 3, further comprising the stepof at least one processor determining a score for the first signature ofthe first software package.
 5. The method of claim 4, wherein the stepof at least one processor determining the score for the first signatureof the first software package comprises the steps of: multiplying by afirst value each file of the files of the first signature that are notthe one or more critical artifacts, wherein the files of the firstsignature each have a starting score of unity, and wherein the firstvalue is a first percentage; and multiplying each file of the files ofthe first signature that appear in the files of the second signature bya second value, wherein the second value is a second percentage that islarger than the first percentage.
 6. A computer program product fordetermining and scoring a signature for a software package, the computerprogram product comprising: one or more computer-readable tangiblehardware storage devices and program instruction stored on at least oneof the one or more hardware storage devices, the program instructionscomprising: program instructions to compare files on a clean computersystem after installation of a first software package to files on theclean computer system before installation; program instructions todetermine a first signature of the first software package, wherein thefirst signature comprises files on the clean computer system afterinstallation of the first software package that were not present on theclean computer system before installation; program instructions tocompare files remaining on the clean computer system after an uninstallof the first software package to the files on the clean computer systemafter installation of the first software package; and programinstructions to determine one or more critical artifacts of the firstsignature, wherein the one or more critical artifacts comprise files ofthe first signature not remaining on the clean computer system after theuninstall of the first software package.
 7. The computer program productof claim 6, further comprising: program instructions stored on at leastone of the one or more hardware storage devices, to compare files on theclean computer system after installation of a second software package tofiles on the clean computer system before installation; and programinstructions stored on at least one of the one or more hardware storagedevices, to determine a second signature of the second software package,wherein the second signature comprises files on the clean computersystem after installation of the second software package that were notpresent on the clean computer system before installation.
 8. Thecomputer program product of claim 7, further comprising: programinstructions stored on at least one of the one or more hardware storagedevices, to compare files remaining on the clean computer system afteran uninstall of the second software package to the files on the cleancomputer system after installation of the second software package; andprogram instructions stored on at least one of the one or more hardwarestorage devices, to determine one or more critical artifacts of thesecond signature, wherein the one or more critical artifacts comprisefiles of the second signature not remaining on the clean computer systemafter the uninstall of the second software package.
 9. The computerprogram product of claim 8, further comprising program instructionsstored on at least one of the one or more hardware storage devices, todetermine a score for the first signature of the first software package.10. The computer program product of claim 9, wherein the programinstructions to determine the score for the first signature of the firstsoftware package comprise: program instructions to multiply by a firstvalue each file of the files of the first signature that are not the oneor more critical artifacts, wherein the files of the first signatureeach have a starting score of unity, and wherein the first value is afirst percentage; and program instructions to multiply each file of thefiles of the first signature that appear in the files of the secondsignature by a second value, wherein the second value is a secondpercentage that is larger than the first percentage.
 11. A computersystem for determining and scoring a signature for a software package,the computer program product comprising: one or more processors, one ormore computer-readable memories, one or more computer-readable tangiblestorage devices and program instructions which are stored on at leastone of the one or more storage devices for execution by at least one ofthe one or more processors via at least one of the one or more memories,the program instructions comprising: program instructions to comparefiles on a clean computer system after installation of a first softwarepackage to files on the clean computer system before installation;program instructions to determine a first signature of the firstsoftware package, wherein the first signature comprises files on theclean computer system after installation of the first software packagethat were not present on the clean computer system before installation;program instructions to compare files remaining on the clean computersystem after an uninstall of the first software package to the files onthe clean computer system after installation of the first softwarepackage; and program instructions to determine one or more criticalartifacts of the first signature, wherein the one or more criticalartifacts comprise files of the first signature not remaining on theclean computer system after the uninstall of the first software package.12. The computer system of claim 11, further comprising: programinstructions which are stored on at least one of the one or more storagedevices for execution by at least one of the one or more processors viaat least one of the one or more memories, to compare files on the cleancomputer system after installation of a second software package to fileson the clean computer system before installation; and programinstructions which are stored on at least one of the one or more storagedevices for execution by at least one of the one or more processors viaat least one of the one or more memories, to determine a secondsignature of the second software package, wherein the second signaturecomprises files on the clean computer system after installation of thesecond software package that were not present on the clean computersystem before installation.
 13. The computer system of claim 12, furthercomprising: program instructions which are stored on at least one of theone or more storage devices for execution by at least one of the one ormore processors via at least one of the one or more memories, to comparefiles remaining on the clean computer system after an uninstall of thesecond software package to the files on the clean computer system afterinstallation of the second software package; and program instructionswhich are stored on at least one of the one or more storage devices forexecution by at least one of the one or more processors via at least oneof the one or more memories, to determine one or more critical artifactsof the second signature, wherein the one or more critical artifactscomprise files of the second signature not remaining on the cleancomputer system after the uninstall of the second software package. 14.The computer system of claim 13, further comprising program instructionswhich are stored on at least one of the one or more storage devices forexecution by at least one of the one or more processors via at least oneof the one or more memories, to determine a score for the firstsignature of the first software package.
 15. The computer system ofclaim 14, wherein the program instructions to determine the score forthe first signature of the first software package comprise: programinstructions to multiply by a first value each file of the files of thefirst signature that are not the one or more critical artifacts, whereinthe files of the first signature each have a starting score of unity,and wherein the first value is a first percentage; and programinstructions to multiply each file of the files of the first signaturethat appear in the files of the second signature by a second value,wherein the second value is a second percentage that is larger than thefirst percentage.